Contact shoe for conductor rail



July 7, 1959 E. A. HARKINS, JR

CONTACT SHOE FOR CONDUCTOR RAIL Filed May 17. 1956 can r I .I

25 6 mm am f j V INVENTOR a 50/50 A. l/AQk/A/S J2.

298mm 44k All; ATTORNEJ 2,894,078 Patented July 7, 1959 CONTACT SHOE FORCONDUCTOR RAIL Edison A. Harkins, In, Bordentown, NJ.

Application May 17, 1956, Serial No. 585,454

" Claims. (Cl. 191-45) This invention relates to a contact shoe forcollecting current from the conductor rails which transmit power tocrane hoists and the like. More particularly, it is concerned with theproblem of eliminating failure or loss of power as the result of dirtaccumulating on the conductor rail. In this respect, the inventioncontemplates improvements in conductor rail contact shoes which areeffective in the removal of dirt from the conductor rails and whichprovide a self-cleaning action for clearing the shoe of dirt removedfrom the rail.

Eflicient transfer of power from a conductor rail is dependent on itshaving good electrical contact with the current collecting shoe ortrolley wheel on a crane or other trolley carriage. Collections of dirtand grease on the conductor rail can and frequently do interfere withthe electrical contact between the rail and current collecting shoe andthus cause a loss or failure of power. In such case, the shoe in movingover the rail gathers the dirt in front of its direction of movement andits continued movement may result in the dirt being rolled between theshoe and rail with a wedging action. In this manner, the dirt may beeffective to raise the shoe relative to the rail and thereby provide apoor contact if not an open circuit and consequent failure of power. Theelimination of power losses and failures of this character is one of theprincipal objects of this invention. Another object of the invention isto provide improvements in contact shoes which are operative to removedirt and grease from a conductor rail while maintaining an effectiveelectrical contact therewith.

The above and related objects of the invention are accomplished by theprovision of a contact shoe in which a plurality of current collectingconductor bars have simultaneous sliding contact with the rail. The shoeincludes a common supporting structure for moving the conductor barsover the rail and on which the conductor bars are mounted forindependent movement relative to each other and relative to suchsupporting structure. This provision for independent movement in amanner to be described enables one or more of the conductor bars to moveout of electrical contact with the rail without interrupting the currentcollecting elfectiveness of the shoe. Incidental to this feature of theinvention, each of the conductor bars has an electrical connectionthrough a shunt circuit to a power transmitting cable which isindependent of a circuit to such cable through the metal parts of theshoe.

Further details and advantages of the invention will be come apparentfrom the following description. In the drawings, there is shown apreferred embodiment of the invention. In this showing:

Figure l is a plan view in which a pair of contact shoes constructed inaccordance with the principles of this invention are shown in theiroperative positions with respect to a pair of vertically spacedconductor rails;

Figure 2 is a front elevational view looking in the direction designatedby the line IIII in Figure 1; and

Figure 3 is an enlarged detail and fragmentary sectional view of aportion of one of the shoes shown in Figure 1.

As indicated above, the contact shoe of this invention is particularlysuitable for the purpose of collecting current from conductor railswhich extend along the trackway for a trolley carriage such as onesupporting an overhead crane hoist. The power collected by the shoe isof course transmitted as in conventional practice to the drive for thecarriage and the crane or other mechanism carried thereby. In thedrawings, horizontal conductor rails are designated by the numeral 1 andit will be understood that such rails extend along the trackway (notshown) for a crane or other carriage (not shown). The numeral 2designates a wood standard which is secured to the carriage (not shown)for movement therewith and which mounts a pair of contact shoes 3a and3b respectively constructed in accordance with the principles of thisinvention. As in conventional practice, the contact shoes 3a and 3bcollect current from the conductor rails 1 and form part of theenergizing circuit for the drive mechanism on the carriage to which thestandard 2 is secured. As best shown in Figure 2, the standard 2 mountsupper and lower contact shoes 3a and 3b which respectively collectcurrent from vertically spaced rails 1a and 1b. The structures of theshoes 3a and 3b are identical and the ensuing description applies toboth.

Each of the shoes 3a and 3b comprises a supporting bracket 4 having arms5 which are connected by a horizontal pivot pin 30 to the standard 2 forpivotal movement about an axis parallel to the conductor rail 1. Thebracket 4 may be conveniently constructed by bending a steel strap tothe U-shaped configuration shown in the drawings. A brace bar 6 has itsends welded to and braces the arms 5 against movement relative to eachother. The bar 6, bracket sides 7 and bracket end 8 define an opening 9which is centered over the conductor rail 1 when the bracket 4 is in itsoperative position as shown in the drawings. By reason of its pivotalsupport, each bracket 4 has a gravitational bias for pivotal movement ina counterclockwise direction as viewed in Figure 2 to its operativeposition. The bracket sides 7 are angularly inclined transversely of thelength of the conductor rail 1 for a purpose to be described.

A current collecting assembly of a plurality of parallel contact bars orplates 11 respectively extending transversely of the conductor rail 1 isarranged centrally of the bracket opening 9. As best shown in Figure 2,the conductor bars or plates 11 have a rectangular shape and a verticaldimension greater than the bracket sides 7 so that a bottom portion 12projects below the lower edge 13 of the bracket 4 for sliding engagementat its center with a conductor rail 1. The mounting of the conductorbars 11 on the bracket 4 comprises a pair of rods 15 respectivelypositioned on opposite sides of the rail 1 and which extend throughaligned openings 17 and 18 in the bracket sides 7 and in opposite endsof the conductor bars 11. Washers 16 on the rods 15 space the rods 11relative to each other. As best shown in Figure 3, the diameter of theopenings 17 and 18 is greater than the diameter of the mounting rods 15extending therethrough. By reason of the angular inclination of the axesof the openings 17 and 18 relative to the mounting rod 15, the conductorbars 11 and rods 15 are restrained against movement in a horizontaldirection extending lengthwise of the bars 11. However, and since theopenings 17 and 18 have a greater vertical dimension than the rod 15, itwill be apparent that each of the bars 11 may move vertically, that is,in a direction normal to the plane of the drawing as viewed in Figures 1and 3, relative to the remaining bars 11 and to the bracket 4 for apurpose to be described. This mounting of the bars 11 provides for theirmovement both toward and away from the rail 1 in a vertical directionwhich is transversely of their path of movement over the rail 1.

Current collected by each shoe 3a and 3b is transmitted through a cable20 to the drive mechanism for the crane carriage. 20 in electricalcontact with one of the bracket sides 5 so that current collected by theconductor bars 11 is conducted through the metal parts of the bracketto'the cable 120. To avoid pitting of the supporting rods 15 by currentconducted in this manner and to insure an electrical con- A clamp 21secures one end of the cable" nection between each of the bars 11 andthe cable 20, there is provided a shunt circuit which is comprised of apair of conductor leads 22 and a bridging conductor 23.

The bridging conductor 23 has a soldered connection 24 with eachconductor bar 11 at a point centrally of its upper edge. One terminal ofeach of the leads 22 has a soldered connection 25 to the bridgingconductor 23 and its other terminal 'is secured by the clamp 21inelectrical contact with the cable 20. In this manner, the currentcollected by each of the conductor bars 11 may be transmitted directlyto. the cable 20 through the bridge conductor leads 23 and 22 withoutgoing through the metal bars 11 and bracket 4 provides a gravitationalbias for maintainiing the lower edge 12 of each bar 11 in contact withthe rail 1. However, the dimensional diiference between the openings 18and mounting rods 15 in a vertical direction as described above enableseach bar 11 to move vertically relative to the others and withoutimparting movement to the bracket 4 as it moves over elevations on therail 1. In this manner, upward movement of one of the conductor bars 11is ineffective to interfere with the electrical contact of the remainingbars with a conductor rail 1. The angular inclination of the bars 11 isof course effective to move dirt laterally from the rail 1. In the eventthat any dirt or grease on a conductor rail moves under and elevates oneof the bars 11 out of electrical contact therewith, an electricalcontact will be had through the remaining bars. Alternate bars 11 arepreferably fabricated of steel and brass plates; the steel platesproviding improved wear resisting prop connecting said conductor straps,and means mounting said bracket on said support.

2. A contact shoe assembly for collecting current from a conductor railcomprising a bracket of conductive material, a pair of spaced parallelrods carried by said bracket, said rods being made of conductivematerial, a plurality of conductor straps extending transversely of saidrods and having openings in the ends thereof through which said rodsproject to support said straps on said bracket, said openings beinglarger than said rods in a direction generally normal to the planethrough the axes of said rods so that said straps have limited movementrelative to each other and to said bracket, a support, and meansmounting said bracket on said support.

3. A contact shoe assembly for collecting current from a conductor railcomprising a support, a bracket of conductive material, a pivotalconnection between said bracket and said support, a pair of spacedparallel mounting rods carried by said bracket parallel to the axis of"said pivotal connection, a plurality of conductor straps havingopenings in the ends thereof through which said rods project to supportsaid straps on said bracket, said straps extending transversely of saidrods, said openings independently of said bracket and strap mountingrods.

4. A'contact shoe assembly for collecting current from a conductor railcomprising a support, a bracket of conductive material, a pair of spacedparallel mounting rods carried by said bracket, a plurality of conductorstraps erties and the brass plates providing improved conductorproperties in the shoe.

As shown in Figure l, the bars 11 and bracket sides 7 in the upper andlower shoes 3a and 3b have angular inclinations in reverse directions.and grease removed from a conductor r-ail by the upper shoe will notgravitate onto the lower shoe.

While one embodiment of my invention has been shown and described itwill be apparent that other adaptations and modifications may be madewithout departing from the scope of the following claims.

I claim:

1. A contact shoe assembly for collecting current from a conductor railcomprisinga bracket of conductive material, a pair of spaced parallelrods carried by said bracket, a plurality of conductor straps extendingtransversely of said rods and having openings in the ends thereofthrough which said rods project to support said straps on said bracket,said openings being larger than said rods in a direction generallynormal to the plane through the axes of said rods so that said strapshave limited movement relative to cachother and to said bracket, asupport, flexible means for conductively inter- In this manner, dirthaving openings in the ends thereof through which said rods project tosupport said straps on said bracket, said straps extending transverselyof said rods, said openings being larger than said rods in a directiongenerally normal to the plane through the axes of said rods so that saidstraps have limited movement relative to each other and to said bracket,a connection mounting'said bracket on said support for movement in adirection normal to a plane through the axes of said rods, and flexiblemeans for conductively interconnecting said conductor straps.

5. A contact shoe assembly for collecting current from a conductor railcomprising a support, a bracket of conductive material, a pair of spacedparallel mounting rods carried by said bracket, said rods being made ofconductive material, a plurality of conductor straps having openings inthe ends thereof through which said rods project to support said strapson said bracket, said straps extending transversely of said rods, saidopenings being larger than said rods in a. direction generally normal tothe plane through the axes of said rods so that said straps have limitedmovement relative to each other and to said bracket, and a connectionmounting said bracket on said support for movement in a direction normalto a plane through the axes of said rods.

References Cited in the file of this patent UNITED STATES PATENTS959,197 Belzner May 24, 1910 2,003,209 De Saint-Martin May 28, 19352,582,440 Keaton et al. Jan. 15, 1952 2,699,597 Arms Jan. 18,1955

